Both $\>x\>$ and $\>y\>$ denote functions of $\>t\>$ that are related by the equation $\>9x^{2}+16y^{2}= 1$.
Use this equation and the given information that $\>dx/dt = -7\>$ to find $\>dy/dt\>$ when $\>(x, y) = (\frac {1} {3 \sqrt{2}}, \frac {1} {4 \sqrt{2}})$.

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